Policy and Charging control (PCC) is a policy and charging control mechanism defined by the 3rd Generation Partnership Project (3GPP). An architecture of PCC is shown in FIG. 1.
A core of the PCC mechanism is that when establishing a data flows bearer, a Gateway device requests a data flow control and charging policy from a Policy and Charging Rules Function (PCRF) entity; according to subscriber information stored in a Subscription Profile Repository (SPR), information about a bearer layer provided by the Gateway, and some local policies configured in the PCRF by an operator, the PCRF generates a dynamic charging and control policy about a service data flow or determines a to-be-activated static charging and control policy about a service data flow, and delivers a command to the Gateway to install the generated dynamic policy or activate the determined static policy that is stored in a Policy and Charging Enforcement Function (PCEF); and the Gateway performs resource allocation, data flow control, and charging control according to the installed/activated policy. The mechanism can implement precise control over a service data flow according to an operator policy, so as to implement refined operation on bandwidth.
Related concepts are defined as follows.
The PCEF entity is located in the Gateway and is configured to execute a dynamic or static control policy. The Gateway includes an endpoint established on a bearer, such as a Gateway General Packet Radio Service (GPRS) support node (GGSN) or a PDN Gateway (P-GW).
The PCRF entity is responsible for generation of policies of Quality of Service (QoS), bandwidth, gating control, charging, or the like when user equipment uses a service in a home network.
The SPR stores user subscription data and maps to an entity in an existing system, where the entity may be a home location register (HLR), a Home Subscriber Server, (HSS), an Online Charging System (OCS), or the like.
A Traffic Detection Function (TDF) unit is configured to detect an application. Detection herein does not refer to parsing using a 5-tuple at a network layer, but refers to deep packet parsing.
The OCS receives a charging event and user use information that are reported by the PCEF after the PCEF is triggered.
A rating group (also referred to as Rating Group) is used to aggregate one or more services having same costs (also referred to as cost) or a same rating (also referred to as Rating) type, and is used for charging system rating.
In a long term evolution (LTE) network, a user mobile phone is always connected to a network (also referred to as Always-on). To implement Always-on, when being attached, the mobile phone establishes a default bearer (also referred to as Default Bearer), where the bearer exists at an entire stage in which the user is connected to the network.
When a mobile phone is in an Always-on mode, no matter whether a user uses a service, at least one Internet Protocol (IP)-Connectivity Access Network (CAN) Session exists. One IP-CAN Session involves session establishment on multiple interfaces such as Gy and Sd, and the session is maintained in entire IP-CAN Session duration, which causes a waste of resources of an OCS, a PCEF, or the like.